Automatically optimizes your pages to minimize the number of network connections and ensure even third party resources won't slow down page rendering.
https://www.cloudflare.com/features-optimizer
Analytics and Tracking · Application Performance
Get access to data on 555,271 websites that are Cloudflare Rocket Loader Customers. We know of 32,186 live websites using Cloudflare Rocket Loader and an additional 523,085 sites that used Cloudflare Rocket Loader historically and 16,159 websites in the United States.
Get a list of 555,271 websites using Cloudflare Rocket Loader which includes location information, hosting data, contact details, 49,350 currently live websites which includes 17,164 domains that redirect to sites in the list. 523,085 sites that used this technology previously and 16,159 websites in the United States currently using Cloudflare Rocket Loader.